Question

Simplify the following expressions: (4a+5b) (4a+7b) – (3a+4b) (3a+6b)​

Answer 1

Here is the answer ↓.

$= 4a ( 4a + 7b ) + 5b (4a + 7b ) - { 3a (3a + 6b ) + 4b ( 3a + 6b )$

$= 16a^{2} +28ab+2ab+35b^{2} -{9a^{2} +18ab+12ab+24b^{2}$

$= 16a^{2} + 48ab + 35b^{2} - 9a^{2} + 30ab + 24b^{2} \\\\= 16a^{2} - 9a^{2} + 48ab-30ab +35b^{2} - 24b^{2}\\\\ = 7a^{2} + 18ab + 11b^{2}$